e1000e: Add code to check for failure of pci_disable_link_state call

This patch attempts to work around a problem found with some systems where
the call to pci_diable_link_state_locked() fails.  As a result, ASPM is not,
in fact, disabled.  Changing disable ASPM code to check if state actually
is disabled after the call and, if not, try another way to disable it.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Acked-by: Bruce W. Allan <bruce.w.allan@intel.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>